Dual fuel system



June 14, 1960 F. A. NEMr-:c EVAL DUAL FUEL SYSTEM Filed March '7, 195'72 Sheets-Sheet 1 June 14, 1960 F, A.' NEMEC EI'AL DUAL FUEL SYSTEM 2Sheets-Sheet 2 Filed March 7, 1957 h\\ whv Qui.

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United States Patent" DUAL FUEL SYSTEM Fred A. Nemec, 9030 Colima Road,Whittier, Calif.; Elwood C. Martin, 32 Harbor Island, Newport Beach,Calif.; and Robert W. Nemec, 9600 La Alba Drive, and Raymond E. Nemec,8933 Colima Road, both of Whittier, Calif.

Filed Mar. 7, 1957, Ser. No. 644,687

18 Claims. (Cl. 12S-139)' The present invention relates to a dual fuelsystem for Diesel engines wherever such a system would proveadvantageous and economy of operation would result.

The dual fuel system of the invention has been found to be of use formarine Diesels, Diesel tractors, so-called stationary Diesels, and inDiesel locomotives. It has been determined that in the case ofrailroads, that railroad fuel alone accounts for about 50% offlocomotive operating expense and, accordingly, a system which permitsthe railroad to cut its fuel hills .from 11/2 to 2 cents per gallonwill, in the aggregate, result in a saving nancially to the railroad.

Actual experience has dictated that a residual fuel, such as Bunker Cand blends of residuum and distillate oils, hereinafter referred to asresidual fuels, cannot be used Ifor starting Diesel engines, or whilethe said engine is idling, without great damage to the engine after aperiod of time. As a consequence, residual fuels of the type mentionedare generally used after the engine is delivering a certain horsepoweror revolving at a given speed, under load. When residual fuels are usedthroughout the range of the engine, that is, from starting to itshighest speed or horsepower, injection difficulties result at the lowspeeds or idling, due to the high viscosity of the residual fuel, andthe high corrosive factors of this fuel at llow engine temperatures havea deleterious elect on the engine, and particularly the cylinder linersand piston rings. This is due to a large number of contaminants inresidual fuel which include sulphur and derivatives thereof, such assulphuric acid, and the formation of hard carbon cones or horns at theengine injector tips. Quite obviously, the cost of overhauling a Dieselengine and its reduced availability resulting from the use of residual-fuels at low speeds is so high as to cause the railroads to utilize ahigher grade fuel to overcome the ydiiiculties mentioned. lIn otherwords, it is more economical for the railroads to use a distillate fuelthan to stand the cost of an overhaul throughrthe use of a residual fuelfor the low speeds. However, a railroad engine, or other Diesel engine,will not idle properly, nor will it deliver peak performance at lowoperating speeds or loads with a residual fuel irrespective of thedamage that such a fuel causes the engine. Accordingly, it is proposedto utilize a high grade fuel, such as a distillate, for low enginespeeds and loads and at idling and starting, and then to transfer to aresidual fuel after the engine is Idelivering a selected horsepower andis operating under a load. To effect economical operation of such aDiesel engine, it is obvious that the high grade fuel should not beutilized for a longer period than is absolutely necessary yfor theobtaining of peak eiciency in the engine operation. However, it isessential that the residual fuels should be conditioned for use in theengine. The viscosity of a residual fuel, such as Bunker C, is so highthat at ordinary temperatures, it practically will not ow and,accordingly, this residual fuel must be heated. The present inventionprovides a means Patented June 14, 1960 ICC whereby the residual fuel isheated by utilizing a heat exchanger in connection with the engine waterjacket, which water is used for cooling the engine. Other sources ofheat may be utilized, such as the exhaust stackor electric heaters. Ithas been found that Bunker C blended residual (viscosity of 300 SSU atF.) when heated to F., has an injection viscosity of around 80 SSU. Asstandard distillate fuel has a B.t.u. content of 140,000, the gravitybeing 36, while a 13.5 API gravity residual has 150,000 B.t.u. pergallon, there is a possible increase in per gallon mileage through theuse of the high B.t.u. content residual fuel over standard distillate ofabout 7.2%. Accordingly, then, the problem is to utilize a high gradefuel, such as a distillate, for starting, idling, and for certain loadconditions, and thereafter to automatically transfer to a heatedresidual fuel for the remaining speeds and horsepower of the enl gine.

An object of the present invention is primarily to effect 'economies inDiesel engine operation so far as fuel is a factor, by the utilizationof a dual fuel system which, when used in accordance with the presentinvention, results in eicient engine operation throughout theoperatingrangeof said engine. j j

A further object is to provide eicient means for automatically changingfrom one fuel to another vf uel in accordance with the operatingconditions of the engine.

A further object is to provide a system and means whereby use of a heavyresidual fuel may be discontinued and a distillate fuel used, and viceversa, without any intermingling or contamination of the content of thelight fuel tank by heavy fuel.

A further object is the provision of a system and means adapted toautomatically enable a Diesel engine to operate a majority of itsworking cycle on a low grade, economical fuel.

A further object is a Idual fuel system for Diesel engines which sofunctions during a change from residual or low grade fuel to high gradefuel, such as a distillate, which purges the injector manifolds of theengine and intermediate feed lines of all low .grade or residual fuelprior to receiving the high grade or distillate fuel, to the end thatthe engine does not have any intermixing between the fuels, particularlywhen the engine is idling.

A further object is the provision of a system and means utilizing dualfuel lfor a Diesel engine, which is adaptable to either manual orautomatic operation and wherein there is incorporated means which isfoolproof in operation, not critical, and parts which, when onceadjusted, will retain adjustment. Particularly, the system and meansdoes not require constant attention hy lan engineer to determine whetheror not the system and means is functioning properly. All controls lforthe system of the present invention are so arranged that the engineermay easily observe the same and any likelihood ofbreak down is reducedto a minimum.

With the above and other objects in view, the invention consists in thenovel and useful provision, formation, construction, association, andrelative arrangement of parts, members and features, all detailed in thedrawings, described generally, and more particularly pointed out in theclaims.

In the drawings:

Figure 1 is a schematic piping arrangement together with parts andmembers utilized in the dual fuel system of the present invention,

Figure 2 is a fragmentary, longitudinal sectional view of selectorvalves utilized in the present invention,

Figure 3 is an enlarged sectional view of a time delay unit used in thepresent invention,

'3 Figure 4 is a transverse sectional View on the line 4-4 of Figure 3,and,

Figure is a sectional `View of a filter relief valve utilizediu theinvention.Y e 1 j l Referring `nowwith particularity to the drawings,Ythe basic ,dual fuel system is jshown .diagrammaticallye in .Figure ;1,While certain apparatus and meansutilized in 4said,fsystemis detailed-intheremaining figures. Initially,

inFigure l bear notations to give a clearunderstanding tofu-tilemembersfutilized in the system. -When consideringvthednalffuel systemforuse inlocomotive, marine and stationary diesels, it is apparent thatcertainrenements of detail may be resorted to, in accordance with thepartcular typer ofengine involved. By this,we mean that a high .grade ordistillatefuel tank must be provided and likewise a residual or lowgrade fuel tank. These tanks maybe separate, or in the form of one largetank with a divideror partition wall separating and forming twocompartments, one for high grade fuelY and one for low grade fuel; Ithas been found expedient to treat the exterior surface of the fuel tankswith some heat'resistant coating as the system to be described'requiresa heat Y treating of the residual fuel so that its viscosityis loweredvto permit the sameto flow. Thus, 'in Figure l, there is' agpiping 1which leads at 2 to theresidual or heavy fuel tank, while the piping at3 leads to the distillate orhigh grade fuel tank. 2 also represents theo-utlet to the heavy fuel tank while the pipes at 4 and 5 constituteVVthe inlets from 'theheavy fuel tank. 'Thus two lines, such as 4 and S,serve toconduct the residual fuel from the residual fuel tank to thevarious elements of the system, while the pipe `2 acts to returnthefheavy fuel to said tank,V In addition to the foregoing, there is apipe '6 which discharges to the heavy fuel tank. Thus, We have two pairsof inlet and outlet pipes communicating with the heavy fuel tank. Y 'IVTo describeV the heavy fuel system, thepipes 4 and 5, which constitutethe inlet pipes to the systemof Figure 1, each includes therein a motordriven pump which Yconstitute heavy Yfuel circulating pump 7 and fuelsupply vpum-p 8.V The circulating motor and Vpump atV 7 communicate witha piping 9 vleading to heat exchanger 14), while the combinationmotor-purnpgat'S leadsto piping 11 and heat kexchanger 12. The heatexchangers, inthe present instance, are shown as being helical piping,and

' the varieusparts entering into the diagrammatic vshowiiztgtheheatfexchangers are eonined Withina tank'13.v The Ymunication'lwithth'e pipe 6 which, aspreviously stated,

discharges to the -heavy'fuel tank, while the voutlet for the heatexchanger 12 is in communication with a prie fmary iilter 16 VAby -meansof piping 17.V The outlet piping 1S-from the primary iilter connectsYwith piping '19, which piping Vc'c'xrmniuuicates with piping 17, therebeing a relief connected withfthe motor pump combinationsat 7 and 8.

valve`20 included' in said'piping 19 between pipi-ng Y17 land 18.Therevis a pressure gage 21included in the piping 19, thesaid piping`leading to a final lter selector fvalveV 22. Two separate nal filters23 andV 24 are within the tank Vv13 vand'pipes Z5 and 26 lead fromthe-selector valvefZz-to the-inlets for the -said yfilters 23 and 24,while piping 27 and'29 leads from the outlets of filters '23 and e 24 toa heat exchanger 28. The heat exchanger 28 is identical in constructionto the heat exchangers shown atl() and 12, and the outlet pipe 30fromsaid heat Y exchanger extends outwardly of the tank 13 to a relief.V

t valve 31 andV through said relief valve the said piping as an inletfuel selector valve, and as shown inV the diagram, a pipe 34 is incommunication with pipe'30 and a port in the said fuel valve 33. Afurther fuel valve Y `is provided at 35 which'is identical inconstruction with the fuel valve 33, andthepipe 1 communicates withV aport in said valve.

Fuel valveNo; 2 at 35 is commonly referred to hereafter as a returnfuelselector Yval'e. Included within the pipe 1 is an'oritice 36. A piping37 communicates with piping '1 at 38 `for one end thereof, while theopposite end thereof is in communication with piping 11. included Withinsaidpiping 37 between the piping 11 and its Vconnection with the piping2 is a relief valve 39.

The distillate vor high grade fuel VVsystem has its connection with thedistillatetank through pipe 3 which leads to check valve 49,' a strainer41, a distillate fuel pump 42, and a series of iilters, designatedgenerally as 43. The piping in this connection between the check valve,strainer, and the pump is designated as 44. Piping 45 communicateswithpiping44betweenthe pump 42 and 'the filters 43,V said pipingincluding a relief valve46, the said piping returning to thelightfueltank. Beyond the relief 'valvef46 is piping47 whichincludcs withinits length a relief valve 48, thepiping terminating in a port of the No.lfucl valve'33. Piping y49 com.- municates with the piping .47 betweenthe relief valve 48 and the fuel valve 33, andwith the filter unit l43.VPipingV Y49 includes withinits lengthapressure 'gage 50. Piping 51communicates with a port in fuel'valve 33 and'with the engine manifold,said Vpiping .including within its length a sight glass 52, andpipiug 53communicates with said piping 51 and with a port in fuel .'valve35.Piping 54 communicates witha .port infuel valve 35 Vand .with the enginemanifold orheader.

In the present instance, Ythe fuel valves 33 and.35 are rair operated,and air under ,pressure has vits'inlet atSS through a strainer 56, withian electrofpneumatic Vsolenoid valve 57, and through said solenoidvalve vwith fuel valve No.1, shown at'33. Between the solenoid valve 57and strainer 56 the vair allowedto pass under controlof auvelectro-pneumaticY solenoid valve 58.to fuel valve No. 2, shown at `35.The air under pressure is Lalso,.directed to a time delay unit,designated;as 59,.and which unit is detailed in Figures 3 and 4l The airv.path to the time delay unitis included in the circuit interposedbetween fuel valve V33 and the Ysolenoidv valve 57. This circuitincludes, in the present instance, agage 60. The solenoid valves57'and58 each :have aV bleed port-that opens when the'valves arevclosedto pressureair.

Electrical circuits Yare used 'forenergizing not'only the `severalmotors vconnected -with pumps Ybut for V the Ysolenoid units `as well,and electrical wiring, shown yat 61, connects withaisourcefofjpower,in1this instance,pre`f erably a Y6 4voltD. C. batterycircuit, with manualfmotor starters 62 and 63, which motor.starters areelectrically lA 64-volt D.C. battery circuit is `provided at 64, whichis a positive f circuit while afnegativeecircuitjis provided atV 65, andVaV further positive circuitv at 66.` Circuits -64 vand 66y are passedthrough-fuses 67Vand 68, with Va Vswitching arrangement Yat 69 which isfor automatic operation ofthe dual fuel system when at contact'70 andwhich passes light or distillate fuel only .whenthe Yswitch is atcontact 71 andheavy fuel only when at contact 72; The s witch'armV ofthe switching circuit 69 connects 'through Y 'suitable leads with `arelay Rand with a pair ofetime delay switches 73 Vand73a. Itwill be'observed that the heater elements of switches 73'and 73a areconnected-by wire V74 and by'va wire75 in circuitwith wireswhich includeresistances,.as shown atv 76 and 77.Y V.The wire 76-is in circuit YwiththeV solenoid Yvalve ,57 while Vwire 77 leads *Y Vfrom said solenoidvalvetoaterrninal of yrelay R. YAn

indicator light f7.8y isv connected between wires 76 and 77. elements 79and. 80 of Vswitches 73 and 73u are inten connected by wire 81, and theswitching elements 82 and E83 are interconnected by wire 84. The coil ofrelay R has one terminal connected to wire 75 and the opposite terminalto Wire 81. The switch arm 85 of the relay R connects to wire 84, Whileswitch terminals 86 and 87 are connected to wires 74 and 81,respectively. Switch terminal 87 is connected to wire 77 and with amanually operated switch designated generally as 88, wherein contact 89is known as the delay IN Contact, and contact 90 as the delay OUTcontact, either contact to be engaged by a switch arm. As shown, thereis a connection 91 between line 64 and a contact 92. A further contact93, of a manually operated switch, through connection 94, is in circuitwith the time delay unit 59 and with the solenoid valve 5S and thence toline 65. The switching element for contacts 92 and 93 is designated as95, and this particular switch is known as the PRIMING switch. When thesystem is used in conjunction with a Diesel locomotive, the line 66connects with a single pole-single throw switch in the engine governormechanism, or with a pressure switch in the air line from an automaticgovernor, or from some switch on the throttle lever. So far as the timedelay switches 73 and 73a are concerned, these are of the heaterbi-metallic type, in which the armatures are caused to contact orseparate, in accordance with the heat generated by the heating coil ineach thereof. The relay R has its armature or switch arm S5 movingbetween two contacts 86 and 87, being actuated to move by the magneticcoil within the same.

In order to fully understand the invention, the structure of the fuelvalves No. 1 and No. 2, shown at 33 and 35, will be described, followedby a description of the time delay unit at 59, as well as a descriptionof other elements entering into the various structures utilized in thepractice of the invention.

Referring to Figure 2, a casing or body 96 is provided with acylindrical bore 97 and with an intermediate transverse bore 98 whichforms a port while a diametrically opposite portion of said casing isprovided with four spaced apart bores or ports 99, 100, 101, 102. Itwill be observed that bore 98 is diametrically intermediate bores 100and 101. All of said bores aforesaid are counterbored to provide taperedscrew-threaded portions for reception of threaded ends of fittings orpipes which communicate with said bores or ports, as hereinafter setforth. For instance, the pipes 47 and 53 of the fuel valves at 33 and 35respectively communicate with the ports 101, as shown in Figure 1, whilethe pipes 51 and 54 of said valves are in communication with the ports98. Within the cylindrical bore 97 is a liner or sleeve L. This linerhas a cylindrical outer surface which fits closely within the bore 97and is provided with ports 103 to 107, inclusive, which register withthe ports or bores 98 to 102 of the housing or casing 96. Internally,the liner is provided with a uniform bore 108 centrally of the saidliner and with two larger diameter uniform bores 109 and 110 whichextend inwardly from each end of said liner, there being conicalsurfaces at 111 and 112 joining the uniform bores 108 and 109 in oneinstance and 108 and 110 in a second instance. The conical surfaces,together with the uniform bore 108, function as valve seats. Within theliner are a pair of opposed pistons or plungers 113 and 114. The saidpistons are substantially identical of form and, accordingly, the piston113 will be described, the same features being found in piston 114.

Piston 113 is provided with two cylindrical surfaces of differentdiameters at 115 and 116, with a conical surface 117 joining surfaces115 and 116. Cylindrical surfaces 115 and 116 are adapted to iit closelywithin the bores 109 and 108 of the liner and to assure a fluidtightlit, portions 115 and 116 are provided with annular Vgrooves 118 and119. The piston is provided with an inner reduced diameter cylindricalextension 120, and the piston has an axial bore 121 and counterbore 122,

` to receive an elongated screw 123, the head of the screw beingpositioned in the counterbore 122. v,The large base of the piston isprovided with an inwardly extending, tapered, threaded bore 124 coaxialwith the bore 121, to receive a threaded plug 125.

The piston 114 is provided with an axial threaded bore 126 to receivethe end of the screw 123 for the purpose of holding the two pistons inworking relationship for simultaneous reciprocation. Means in the formof a spacer disc 127 is interposed -between the two piston heads orcontiguous ends of said pistons for adjustment purposes and when the twopistons have been secured together, a set screw 128 carried transverselyof piston 114 will engage the screw 1273 and lock the same againstrotation or movement. The plug is not inserted in the bore 125 untilafter the required adjustment between the piston heads has been made andthe set screw locked in position. The plug 125 assists in preventingaccess of any fuel through the piston in the zone of the screw 123.Coaxial with the bore of the liner L is an elongated cap 192 providedwith a base ange 130, the ange being transversely bored for the passagetherethrough of screws 131 into tapped openings in the casing 96. Theopen end of the cap 129 is provided with an annular flange or shoulder132 which enters the confines of the liner and particularly the enlargedbore portion 109 for assuring that the cap and the said liner are incoaxial alignment. The cap serves as a housing for a master coil spring133, one end of which bears against the inner surface of the head of thecap, while the opposite end bears against the plunger 113 and urges theplunger t0 move in one direction normally to the position shown inFigure 2, which is termed the retarded position.

The opposite end of casing 96 and of the liner and coaxial with saidliner is a stuffing box 134. The stufiing box is anged and screws arepassed through transverse openings of the ange into threaded openings inthe casing 96 for securing the box to said casing. The stufling box, asis usual, is chambered so as to house packing designated generally as4135.

The stuliing box is internally screw-threaded at 136 to receive anexternally threaded gland nut 137 which bears against the packing 135. Anut 138 is carried on threads 137 for locking the position of the glandnut. The stuffing box 134 is externally screw-threaded at 139. A cylin-'der 140 is internally enlarged and threaded, at 141, for

engagement with the threads 139. An annular nut 142 is carried on thethreads 139 for adjusting the Ilthreaded relationship between thecylinder and the stuling box. Within the cylinder is a piston 143. Theinner endof said cylinder is centrally bored at 1'44 and likewiseprovided with a reduced diameter bore 145. The bore v145 houses a ball146, there being an elongated stem 147 passed through the gland nut, thepacking, and a stuiling box for engagement with one end of the piston114, the opposite end of said stern bearing against the ball i146. A cup148 its within the confines of the cylinder and bears against the headof the piston. This cup is provided with a central stud 149. The cup maybe formed of any material desired, such as a tetrauoroethylene resin,commonly known in the trade as Teonf The cylinder is externally threadedat 150 to receive an internally threaded cap 151, the cap of which isflanged externally and internally concentric with 'the center of saidcap, as shown at 152 and 153, thus providing a central bore at 154 andan enlarged central tapered threaded bore 155 to receive the threadedend of a pipe which communicates with air under pressure, or otherfluid, as herein- Vafter set forth. A coil spring -156 of spiral helicalform is interposed between stud 149 and ange 153. 'As shown,

the cylinder is provided with one or more transverse bores 157 to permitviewing the cylinder internally, and particularly the position of thepiston in its movement, and

to permit air to pass in and out of the cylinder.

The timedelay unit 59 is detailed in Figures 3 and 4,

Ystrategists Y and this .unit includes ar'casinglorhousing 158 lprovided1with acylindrical'bore 159 and --counterbore 160 within whichcounterbiore' is .a'liner'161,'-thefinternal diameter Yofthe liner andof the bore 159 `being the san'iegieY casingiis'provided with acircularv end ilange `16:2 having f afatorplaneouter face 163.Anielongated cap member 1.64`isprovided at its openend ywith an annularflange .165, the external vdiameterV of which flange is the same aspacking Vhox,.a11cl.in threaded engagement `with the bei,

' thesaid `stem having an end extension having altapei'ed thestemextension` v,wl'iich is not provided :withthetapered that 'of' 'theange 162. Flange 165 has Ya plane'face 166;

The arrangement is `suchasV to provide an intemalispacing between endwalls 167 and 168 of thebody and the cap.

The head 'of the cap `is provided with a threaded bore for Y receptionof a threaded plug 169. Adapted to be interposed between the flanges 162and 165 is adiaphragrn 170. fI'he diaphragm is provided v`on oppositesides with pads 171 and `172. A stem 173 has a reduced threaded pin 174passed through the pads and the diaphragm-to- Y gether with a'backngwasher, with a nut 175 carried on theY threaded stem for locking theassembly against the shoulder 176 provided between the stem and thereduced rextension 174. The stem is likewise provided with Van extendedaxial pin y177. The cap 164 is adapted to con- Y nea coil spring 178which bearsat one end against the A' received within the counterboreVwhilerthe pin 177 isV passed through the bore 1181 and `into -an axialbore 183 in the piston. The timing cam is provided with a conicalsurface 184, the Vzone of smallest diameter of which terminates adjacentan annular shoulder 185, the periphery of which substantially has adiameter equal to the internal diameter of the `bore y159,V while thebase endV of said Y conical surface merges wih Van annular surfaceY 186fitting within the bore 159. The cup 187 engages the Yhead of thepistomthe cuprbeing formed of some. wear resistant material, such as -aplastic, which may be Teflon Therbody or casing is threaded at ,18S toreceive an internallythreaded cap 189, the cap being formed to'centrally receive the threaded end of a pipe leading to a source ofyaiifc'irfother huid under pressure, as hereinafter set-'forth grooveandfits tightly withinA saidbore when in one-position. The arrangement isYsuch that a' portforbore 212 insaid casing permits communication betweenthe interior of cap 164 and the upper-endet bore 211, at"v-2`13, While'K the opposite end of said -bore-is'in communication with a port 214leading to an yenlarged threaded transverse opening 215, which receivesa pipe 216, thesaid pipe being in communication with la smallfreservoir, not shown in Figure 4 but indicated in Figure 1. Y i

In Figure 5, we have shown, in section, a'lte'r relief Y valve which maybe utilized in the practice of the Yinven- Y. said opening functioningas a valve/seat.

tion, the same including at body Yor casing .217, `the interior ofVwhich is Vthreaded at 218 to .receive "the externally threaded end 219of aiitting'220. The fitting l,is-externally threaded, at 221, forengagement withthe threaded interior of a cap '222. Within 'thecasing-and surrounded in part by the fitting 220 is :a cylindrical coremember 223 having a conical valve head 224. The conical Vvalve head isadapted to be in partreceivedV within'or raised from an opening 225 inthe casing 217, an `edge bounding interposed between thc .said conicalvalve'h'ead yand surrounding-the core, is'a coil .spring Y'226, .withone iend of said spring engaging an end of an.annular-adjusting-serew227.: This adjusting screw is-enternallythreadedffor engagement with the internal-threads 228 'ofthe fitting220, the 'core otherwise being received within .the said adjustingscrew, as shown. A lock nut 229 iscar'riedon` the threads of theadjusting -screwjfor holdin'grt-he'said screw in -any'selected positionand thereby regulating compression of Ythe spring 226,V and Ihenceopening movementof thevalve 'head from its valve seat. [A .port at1230permits Ventrance within the confines of the body or casing.V` Y sReference-is again made to .Figure l. The pipe 55 leads 'to a source'ofair or otherfluid under pressure, and

in the statement of operation. vBetween'the cap 'ande-the Y.

. cupl87 is -a coil spring V190, which'functions as a retainer spring,While the'springY Y178 is designated as .the master spring; Secured Vtothe ftop ofthe body or casing an adjustable'pad 1911 by means of screws,designatedjgen- 'Yera'llyas 192, whicharefreceivedin tapped openings inthe-said casing, and carried on the vadjustable pad, is `a micro-switchA193. The casingand the pad 191 are transversel'yV boredatv194Yto-accom1nodate thevmicroswitch plunger 195. The vcasingVisgirovided with 'a yreduced diameter bore 196vcoaxial with lbore 194,and within this bore r*is received for free movement pin .197, one endof 231 beingcontrolledas'to passage of air 'by the solenoidisprimanlydirected-from said. source through :an air inlet-strainer v56 ofanytype, such asl-the Norgren 'type O-552. After-leaving the.inletfstrainer 56, 'the air .is divided intotwo paths, :as ,show/natV231 and vi282., path operated valve-58 while pathr 2321seontrolled'as'tofpassage of air'by'the solenoid'val've l57.,Solenoidva'lves .are common in the art, andthe walvefis opened A1whenIthe solenoid is energized, and closed :when die-energized.

SuchY controls are available krthrough'-.General '.Controls whichlengages theend of the plunger`195 ofv the micro- Vswitch 193, Thisallows for Vadjustment of therange of lmovement of the timing cam toraise and t'o'rlower the Y pin 197 to a'ctuateV the micro-switch 195.

' A metering valve assembly, designated generally as 198, is shown'inFigurev4, and this assembly is secured to cap 165. The cap is providedwith an external boss.199

which is `internally seres/threaded at 200 to; receive aV threadedextension 201 of casingv 202. A washerV is proa gland nut208,ithe'glandrnut having threaded engagement withthe'threads 206. Anexternally threaded meterring valve stem 209 is'passed through saidgland nut, thek switch and Vthe other end of which pin Aengages, the YVbeveledsuriace of the timing cam. The screws 192 allowVfor"raisingor'lowering of the pad 191 and VVthe. micro- Company, beingits Catalogue'type vPV-ll 1313079, by way or example. After passage vof.theY air from Iline 232 v throughrsolenoid valve 57, the connects withpiping 233. This piping, in 'turmgleadsfin one instance, `to the timeydelay unit shown in ,Figure 3, .and connects also kwith fuel valve No.1, shown'at 33. ;See,also, Figure f2. The-line .2311 after v.passageAt'nroughthe solenoid valve at 58 connects with `fuel Avalve No. 2,shown at 35, the connection being the same as shown for line 233, inFigure 2.V In'Figure l, it willvbe observed ythat Vpipe 47, aftercommunicating with relief valve 48 is in Vcommunicaktion Vwith bore1610i theifuel .'valve33. APipe 34 com- `murnicates with bore 100. (Inthe case of the two bleeder ports, bore99 through pipe 234 is incommunicationV with pipe 1 for fuel valve No. l', shown at-,and bymeansn 'Y yof `a pipe 235 with pipe 1 VfortheNo..Zfuel valveV at 35.

A pipe'236'leadsV frornjbore'102, whi'chfis aKLbl'eeder Vport foreachfuel valve, the said pipe .being connected to pipe 47.v In the caseofthe fuel'valvershown fatv 33, the

lbleeder port isin `connection with'pipe 236A through pipe V37.Asgshown, pipefdS leads to the-distillate'fuel tank.

.The alters as in the distillate fst-,inne ,twin the distillate tankmaybe of-anyrtypegand usually follow the specicatinsl ofv theparticularDiesel fenginebuilder. Y We have found, however, that filters of thestring-wound type, sintered bronze or cartridge types, or a combinationof said types, are satisfactory. The primary filter, shown at 16, isusually of the waste pack lter type, while the nal filters at 23 and 24may be of resin impregnated paper, cotton waste, or other filteringmedia which will readily remove to 25 micron particles.

For convenience, in the statement of the operation, and in describing anembodiment of the invention in actual practice, the several reliefvalves, shown in Figure 1, are designated as to their opening pressureper square inch.

The operation, use and advantage of the invention just described, are asfollows:

In considering the system and means disclosed, certain essentials forits proper operation must be observed. First, in the dual fuel system,the engine must be supplied with a high grade fuel, such as adistillate, during starting and light load conditions, with an automaticswitching to a low grade or residual fuel during high speed and highload conditions, thereafter returning to the high grade fuel as theengine is slowed to a speed unsuitable for economical fuel consumption.Ordinarily, the average diesel locomotive `has a throttle so arranged asto have eight (8) positions, the tirst four (4) positions of which mightbe considered as starting and light load, the engine probably generatingaround 400 horsepower. From the fourth to the fifth position, the dualfuel system makes a change from the distillate or. high grade fuel tothe low grade or residual fuel, and continues to use residual fuel forthe remaining positions, including number eight. In order to use aresidual fuel which has a high viscosity, the fuel must be kept hot inorder that it might be pumped and ltered with ease. 'l'he average dieselengine will not run on residual fuel satisfactorily and Withoutconsiderable damage to the engine when the throttle is in positions oneto four, nor will the engine idle. Itis of utmost importance to guardagainst fouling during the change from residual fuel to distillate orhigh grade fuel that there is a proper purging of the injector manifoldsof the engine, and the intermediate feed lines of all residual fuel.There are times when it is not economically feasible to use residualfuels, even if the engine is running very rapidly, such as during yardswitching in the case of locomotive diesel engines; also docking,entering or leaving locks, etc., for marine diesel engines. The presentinvention is so constituted that even for fully automatic operation,these periods must be anticipated and change over to residual fuelguarded against by the controlling mechanism. Manual overrides foremergency and checking purposes are, therefore, provided in the presentsystem.

The heavy fuel circulating system includes a pair of pipes 4 and 5 whichconnect with the tank holding the residual fuel with the circulatingpump motor 7 and the heavy fuel pump motor 8 driving said fuel into theheat exchangers 10 and 12. In the case of the motor driven pump 7, theresidual fuel, after passing through the heat exchanger 10, returnsthrough pipe 6 to the residual fuel tank, while in the case of the motordriven fuel pump shown at 8, the residual fuel is directed into the heatexchanger 12, and thence through pipe 17 into the primary filter. It isto be observed that the two heat exchangers 10 and 12, together with theprimary filter, and the nal filters at 23 and 24, are positioned withinthe tank 13 which receives hot water from the engine jacket through pipe14 and outwardly through exit 15 for return circulation, to wit, to theexpansion tank. Hence, it is evident, in one instance, that the heatexchanger 10 is directing the residual fuel in a circuitous path to theresidual tank for the purpose of at all times maintaining the residualfuel at a selected temperature, thus keeping the residual fuel at aviscosity suitable for ready handling. Sofar as the motor driven pump 8is concerned, it forces the heated residual fuel through the heatexchanger 12 and into the primary filter 16, which is a coarse filterfor removing deleterious substances in the residual fuel, such assulphur particles, and other abrasive particles, then directing thfiltered residual fuel to a valve 22, which valve may be turned to makea selection of filters 23 or 24. These are known as final filters, anda-re for the further removal of particles from the residual fuel. It isalso evident that if, say, the filter at 23 becomes clogged and createsa back pressure, that the valve 22 may be turned so as to direct theresidual fuel through the second filter 24, followed by replacement ofthe filter 23. From either filter 23 or 24, residual oil is directedthrough the heat exchanger 28 and thence through pipe 30 to fuel valveNo. 1, shown at 33. The relief valve at 20 is set at 40 p.s.i. so thatif excessive back pressure occurs in the primary iilter above the 40p.s.i., the valve will open and allow the residual fuel to directlyenter pipe 19. However, the pressure gage at 21 which operates at 160p.s.i. will give an indication of the back pressure caused by the lilter16 so that the fllter can be replaced. Ordinarily, the residual oil,which is directed to the fuel valve 33 through pipe 34, will build up apressure, particularly if the valve is closed to pas sage of residualoil and when the oil pressure exceeds 30 p.s.i., the relief valve at 31will open and the residual oil will be directed into pipe 1 and returnedto the heavy fuel tank.

The distillate or light fuel is directed from the light fuel tank pastthe check valve 40, through the strainer 41 by pump 42, thence throughfilters at 43, pipe 49, to the No. l fuel valve shown at 33. Likewise,there is a connection 45 between the outlet from the pump 42 and thefilters 43 to a relief valve 46 which opens at 45 p.s.i. with a returnto the distillate fuel tank. There is also a return 47 past the reliefvalve 48, which opens at 30 p.s.i. to the line45 leading to the tank.Thus, if distillate is unable to enter fuel valve 33, under the pumppressure, this distillate will return past the .relief valve 48 into theline leading to the distillate tank, this for the reason that the reliefvalve at 46 will only open at 45 p.s.i. which is 15 p.s.i., higher thanthe setting of relief valve 48.

The Nos. l and 2 fuel valves, shown at 33 and 35, as well as the timedelay unit at 59 are brought into operation through the medium of airunder pressure, the air under pressure being directed in certain pathsto said fuel valves and time delay unit in accordance with the operationof solenoid valves 1 and 2, shown at 57 and 58, these respectivesolenoid valves acting as .pilot valves.

When the coils within tubes 73 and 73E are energized, the thermostaticswitch arms gradually close after a given time delay. These particulartubes are in pa-rallel'to assure the operation of one or the other orboth. thereof at all times. The intermediate tube 71, between the tubes73 and 73a, has its switch element 85 controlled magnetically throughthe magnetic coil therein, and when the elec- Vtrical system is inoperation, assuming that the switch at 69 is placed on contact 70 forautomatic operation, distillate will be directed to the fuel valve 33,which constitutes the inlet fuel selector valve. This valve will be inthe posi tion shown in Figure 2, which is to say, piston 114 is moved soas to allow communication between ports 103 and 106, thence through thepiping 51 to the return fuel selector valve at 35. It will be observedthat pipe 51 leads to the engine header or manifold, as does pipe 54,and while the direction of movement of the fuel oil is in one direction,as indicated by the arrow at the end of pipe 51, the fuel oil is allowedto move in one of two directions so far as pipe 54 is concerned; thepipe likewise leads to the engine header or manifold. We are assuming,of course, that the engine is either idling or the engine throttle hasnot been moved beyond position 4. When position 4 is passed, the switchon the engine governor is closed and the transition from the use ofdistillate fuel to that of residual fuel takes place. v

To review brieliy, the distillate fuel is passed through fuel valves 33and 35 or, as these valves have been designated, the inlet and returnfuel selector valves, to the engine manifold or header, and distillatefuel not used ambush 'zu'Y by the engine is 4returned through reliefvalve 48 to the' inlet or :suctionside of pump 42 or,in certaininstances, to fthe distillate tank. When throttle position 5 or higheris made during a time-interval of, say, 6G seconds, Vthe Velectricalcircuit to the time delay tubes 7,3 and 73a is energized, and theheating coils or iilaments thereinrwill heat the thermostatic switchelements in said tubes and Vfinally close said switch elements. Afteranapproximate time delay lof 60 seconds, aY closing of the switch elementsof .said time delay Vtubes 73 and 73a causes the electrical energizingof Vthe Vrelay R, removing the time delay 'tubes from the circuit andenergizing solenoid valve 57 and likewise energizing the indicator light78.

under pressure to'pass therethrough into fuel valve No. V1,V shown at33, and likewise into vthe timeY delay unit 59. AY closing of the timedelay unit at 59 energizes sole- The solenoid valve 57, upon beingenergized, permits air i noid valve No. 2, shown at 58, and passes airunder Y pressure into fuel valve-No. 2, -shown at 35, this latter valvemoving to heavy fuel oil position. This places 'the engine in heavy fueloperation with unused heavy fuel returning to the heavy fuel tank.

Referencevis made to Figure 2. When air under'pressure entersY thecylinder V140fthrough pipe 233, the pis-V ton 143 is moved Yto the leftof the showing, which movement-will push stem 147 and move the plungeror piston 114 tothe left,'and at the same time, move the piston 113 tocompress the master spring 133. During such movement, piston V171-4 andspecifically the portion 116 will enter the uniform bore portion 108andcloseV passage between ports 106 and 1013. VThis occurs when thepiston'or pistons have moved about 30% of total movement. As the pistons113 and 114 continue moveuniform bore 108 anda conical portion of eachpiston Ymoves relative Ato its conical seat.In the case of piston 114,it tends to close against its conical seat While r piston 113 opens topermit passage through port 105 around the piston into port 103 forresidual oil. All distillate oil -ow has been stopped. This particularvalve is con- Y structedto operate at temperatures from zero'to 303 F.,with a minimum of friction and a maximum of sealing, and will handlefluctuating pressures efficiently.

In the case of the time delay unit, air under pres.

sure enters through pipe`233 into the cylinder to move theipiston 180 tothe Yleft of the showing of Figure 3.

.This time delay unit incorporates a metering valve on one side of thediaphragmV 170. Thus,it is intended 'Y that the vcap'164 vat one siderofthe diaphragm should be lled with oil and that when the diaphragm ismoved in `'one direction, pressureris exerted against the Voil Vtoforce,Vv the same through rport .212, the metering valve and into pipe216, which Vis in direct connection with a small reservoirholding theoil supply. The diaphragm Vis 'moved' against pressure of the masterspring 178 YandY Ydiaphragmrto the left of the Yshowing in Figure 3 tocorn-A press the oil'within the-cap 164. Y During this movement of thepiston, `the timingcam 179 is moved and the pin orplunger 197 Yismovedon the inclined or conical surface of theY timing `camto raise thesame and thus actuatejthe micro switch plunger 1795 to close the microswitch. This closing of the micro switch Yelectrically' actuate's thesolenoid Valve at 5S, which'is'termed apilot valve and'V allows airunder pressure to pass into fuel selector-valve 35. Y

{We assume nowthat the operator or engineer desires" Y v12 to return theYthrottle position to orlWer. During a time interval of, `say, 55seconds, Ithetim'e interval being previously determined, electricalcurrent is imme- -diately -cut 'tothe time delaytube unit, whichdeenergizes 'the solenoid valve 57, lasl-Well as deenergizring theindicator light 78.Y Airis exhausted from fuel valve 33 to theatmosphere and Vthe-pistons 113 and 114 are moved under 'pressure yofYthe master spring 133 to the position shown in Figure 2. The heavy fuelpassageway through port 10S is closed, and the light fuel port'106 isopened. The time delay unit 59 isdeene'rgized in that the air isexhausted from the cylinder, andthe mastersprng 17S moves the piston180and the timing cam 179 to the positionshown in Figure 3, which opensthe micro switch 193. The deenergizi'ng'of' the time delay unit startsthe 55 second timing for Vthe cleaning operation, because the oil mustagainpass the metering stem 209 from its reservoir into the cap 164 andif the metering stem is properly adjusted, this will -requireapproximately `55 seconds time for the opening of the micro switch. As aresult, residual fuel from themanifold is returned tothe heavy fuel tankthrough pipe 1. At the end of the 55V sec- Vment, the portion V116 ofpiston 113 emerges from the onds, as stated, the time delay unit opens,deenergizing solenoid valve 58 and air is released from fuel valve 35.The fuel 'valve y35 returns Ito normal `distillate posi# tion, which isthe position shown in Figure 2.

During the transition from vheavy vor residual fuel to lighter ordistillate fuel, a so-called purgingcycle oc` curs, in that the residualfuel which may remain in the engine header is flushed out withkdistillate fuel; 'this te# sidual fuel, togetherl with the distillatejfue'l required to flush the Yengine header, although small in amount,will be directed'to the heavy or residual fuel tank.

As described, the switch 69 has 'been in the automatic position and thesystenl'operates-.as has Vjust Vbeen set forth. However, 'if `onlydistillate fuel is desired to be used, regardless of the engine speed orload,the switch may be moved'to thelight fuel Contact at 71, and thisposition willkeep all of the valvesV in light fuel operation regardlessof throttle'iposition. The heavy position, or the position shown at 72,keeps.' the selector' valves iti heavy fueleposition. The switch at `88permits either time delay action or the removal ofthe saine whiletesting' the control panel. The indicatorA light at 78 is provided teshow when 'heavy fuel is being supplied to the engineV manifold orheader. This Vlight is extinguished when the engine Yis operated on'light fuel. Y

In order that there shall be no misunde'st'andig as to the operation ofthe syste'l`i1, a brief resume is nitide. T he -two valves 33 and 35 arefor the'purps'e of handling the light and heavy fuels. Specifically, thefuel valve 33 functions as the inlet fuel selector valve Vfor both thedistillate fuel and the residual fuel, while the valve 35 functions asthe return fuel selector valve for either the distillate Vfuelor theresidual fuel. VBoth of these valves 33vand 35 are actuated by air underpressure and the pressure air Ais controlled as to Ymovement 4by thesolenoid valves 57 andeSSf.- YThe electric .solenoid valves are used Vaspilot valves and the piping is such that when one or the other VoftheYsolenoid valves, or both thereof,

Y,are energized, airV under pressure isadmitted to a .fuel

valve 33 or 35, orboth.A When a solenoid valve is deenergiz'ed, air -isreleased therefromand4 a fuel valve 'bew 'comes deenergized'. vThe`solenoid` andfuel valves are lpaired together. .,Thiis, No. lsolenoidvalve 57,:and No. l

fuel valve 33 are p airedfin that No. Vl solenoid Valve operates tovmove thepiston inNo. l fuel'valve, while No.

l 2 solenoid valve 5.8 corit'ls operation of N. 2 fuel valve 35. The No.1 fuel valve",shown' at 33, Controls which fuel, whether residual'o'r.distillate', f.is beingdirected to the engine manifold or header. `,TheNo, Zifuel valve, shown `at 35,' controls' theunused fuel returning fromthe engine manifold'V or header, and .makes it possible ,to purge' themanifold andflines' upon the return to light fuel'. Therefore-,ifsolenoidI valve'o. 1 *is deenergiz'ed,

the engine is using distillate or light fuel. lf the solenoid valve No.1 is energized, then the engine is using residual or heavy fuel. lfsolenoid valve No. 2 is deenergized, the unused fuel in the enginemanifold is being returned to the light fuel tank, and if solenoid valveNo. 2 is energized, the unused residual fuel is returned to the residualfuel tank. The time delay unit59 is located between solenoid valves land 2, shown at 57 and S8, and is for the purpose of assuring thepurging of residual or heavy fuel from the manifold and in the lines onreturn to distillate or light fuel service. When the solenoid valve l,shown at 57, is energized, fuel valve No. l, shown at 33, is moved sothat heavy oil or residual oil is directed to the engine. The time delayunit 59 -is then operated so that solenoid valve SS is opened and fuelvalve 35 is moved so that unused fuel is directed back to the residualfuel tank. When solenoid valve 57 is deenergized, the fuel valve 33directs light or distillate fuel to the engine, and the time delay unit59 moves in a reverse direction, or to the position shown in Figure 3. Atime delay takes place and solenoid valve 5S continues to direct thelight fuel returning from the engine, together with the residual fuelahead of it, back to the residual fuel tank. This is called the purgingcycle. After all residual and mixed fuel is cleaned from the manifold,and clear distillate fuel is visible in the sight glass 52, the timingof the delay unit 59 has run out. Solenoid valve 58 is deenergized andfuel valve 35 then directs the unused fuel to the distillate fuel tank.At this point, the control panel is in its normal position and theengine is on distillate or light fuel. The electrical energy used tooperate the solenoid valves is obtained from the battery circuit of thepower unit, and is coupled ,to the control panel through the automaticswitch or relay units so that when heavy or residual fuel is desired,voltage is present at the control panel. If this electricity is allowedto pass through the electrical panel, solenoid valve 57 would beenergized and light 78 would glow. lt is undesirable to change to heavyfuel and cycle the controls unless it is intended to stay on heavy orresidual fuel for some time. To prevent this unnecessary cycling, thetime delay unit is placed between a terminal and the solenoid valve 57.The ktime delay unit is arranged in such a Way that a predeterminedperiod elapses from the time the voltage is admitted through a terminaluntil it is passed to solenoid valve 57. This timing is for a longenough period to enable the use of high throttle settings for shortperiods without the change over to heavy fuel. The selector switcharrangement shown at 88, 89 and 90 is provided to lock the controis inany desired position so as to by-pass the time delay unit in case thesaid unit should fail, or if operation tis such that said unit isundesirable. We may also provide a so-called purging button for theswitch at 93 which is connected across the time delay unit to make itpossible to manually purge the manifold and to check fuel valve 35 as tooperation. The indicator light at 78 shows which fuel is being used andwhen On heavy fuel is used, and when Off light fuel is used. By-passrelief valves are employed in each fuel system to give a by-pass routefor the fuel not in use.

The operation previously set forth describes an operation or system thatfunctions as a full circulating system during heavy fuel operation andas a dead-ended system during light fuel operation. This means that,when heavy fuel is being supplied to the engine, the heavy fuelcirculates continuously through the engine injector manifold and iscontinuously being returned to the heavy fuel supply tank. When lightfuel is being supplied to the engine, the injector manifold or header isdeadended so that no fuel returns to the light fuel tank. On some Dieselengines, it is desirable to employ a full circulating system on bothlight and heavy fuel operation. This is accomplished by connecting pipe53 to the light fuel tank instead of to pipe 51. ln all other respects,the system would remain the same. In cases where engine design requires,pressurized manifolds, an4 orifice or pressure relief valve 36 is addedto the heavy fuel return line on the down-stream side of fuel valve 35and is used, together with the aforementioned dead-end light fuelconnection. This adaptation would also apply to Diesel engines designed-with a non-circulating or dead-end fuel system.

We claim:

1. Fuel control mechanism for selectively controlling the feeding of twodissimilar fuels from separate fuel supply tanks to an engine manifold,including: a pair of three-way valves, a irst of said valves having twoinle't ports and a single outlet port, the second of said valves havinga single inlet port and two outlet ports, means liow connectingoneoutlet port of the Isecond valve with the outlet port of the firstvalve, the rst valve inlet ports being separately connected with thesupply tanks f or the two fuels, the inlet port of the second valvebeing flow connected to the enginevmanifold, the other outlet port ofthe second valve discharging into the supply tank for one of the fuels,and means responsive to changes in the load and speed of said engine toshift the positions of the pair of valves to change from one fuel to asecond fuel and to prevent contamination between the fuels of at leastone of said fuels.

2. A dual fuel system for suplying two dissimilar fuels to a Dieselengine comprising automatic means for switching from one fuel to asecond fuel and vice versa at a preselected load and speed of saidDiesel engine, and means for purging the fuel supplied to the engineprior to supplying a second fuel to prevent contamination between thefuels. Y

3. A dual supply fuel system for supplying two dissimilar fuels to aDiesel engine, comprising means automatically changing the fuel supplyto said engine from a rst of said fuels to a second of said fuels at apredetermined load and speed of saidengine, and time delay meanscontrolling the first named means when the second of said fuels `is tobe discontinued and the first of said fuels supplied.

4. A fuel system for supplying two dissimilar fuels to the manifold of adiesel engine, comprising: an inlet fuel selector valve and a returnfuelselector valve, the inlet fuel selector valve provided with two inletports and one outlet port, the inlet ports of the inlet fuel selectorvalve being separately connected to the sources of supply of thedissimilar fuels, said return fuel selector valve provided with twooutlet ports and one inlet port,the outlet port of the inletfuelselector valve being connected with one outlet port of the return fuelselector valve and likewise to the engine manifold, the other outletport of the return fuel selector valve being connected to one source ofsupply of a dissimilar fuel and time delay` means for maintaining thereturn fuel selector valve in a, given position to permit purging of afuel from the en gine manifold.

5. A fuel system for supplying two dissimilar fuels to a diesel enginesuch as a light fuel and a heavy fuel, comprising an inlet fuel selectorvalve for controlling the passage therethrough to said engine of eitherthe light or the heavy fuel, a return fuel selector valve con-` trollingthe disposition of the return of any excess of fuel not consumed by saiddiesel engine, said inlet fuel selector valve moving from light fuelsupply position to heavy fuel supply position and Vice versa at apreselected load and speed of said diesel engine, and time delay meanscontrolling operation of the return fuel selector valve to Vhold thesaid valve in heavy fuel position before returning to light fuelposition to permit the heavy fuel to be purged from said diesel enginebefore the return fuel selector valve position changes to light fuelposition.

6. A fuel system for supplying two dissimilar fuels to a diesel enginemanifold, such as a light fuel and a heavy fuel, comprising means forconstantly circulating.

and heating a source of heavy fuel to lower its viscosity,

' permit circulation from the engineV manifold i a Diesel enginemanifold, suchias alight fuel heavy -fuel and yt'lieother ofsaid ports,

Y of-*said Diesel engineya return fuel selecto? Y"is and yineens for'Constantly fn'psiyjisg hufiger anda connection between thsoiii'e fofnfuelfxvith one of said ports and a connection between the s ou'rce ofheated `heavyfnel and the other of said pons, the o'iitlet of said'inlet fuel Vselector valve leading to the m ofsid diesel engine; iareturn, fuel s electonvlve having Y of Sata perte of esta return nieteeieetsr valve hangin connection-with the fsupply ofheavyfliel, andautomatic means for the inlet fuel selector 'valve from light fuel toheavy fuel responsive to a preselected speed and load on said engine.`

7. A'fuel system for supplyi gtwo dissiniilarf fuels to pressureconnection wvitlrthe inlet andputlet 4of Said a diesel engine manifold,such as alight fuel 'anda heavy e fuel, comprising means for constantlycirculating and heating a source of heavy fuel to lower' its viscosity,and means for constantly supplying light fuel fr'o'n a source underpressure, `a three-'Way inlet fuel selector valve hving two inlet portsand a single outletY port, anda 'c on'necl tion between the source oflightfuel with oneof said inlet ports and a connection between thesource of heated heavy fuel and the otheiof said inlet` the outlet portof said inlet fuel selector' valve leading to the rnnifold of saiddiesel engine; a return fuelsel'e'ctoi' valve havingl a single inletVleading vfi'ornY the engine manifold and two separate outlet ports, theoutlet port o f said inlet fuel selectorvalve being'in connection Withone of thesoutlet portsr of said return .fuel selector valve', theotherV o f said outlet ports of saidY retiirn fuel 'select o .valvebeingin connection with the source of supply'of heavy Yfuel,-auton1aticmeasfor shifting' thefinletf 'selector valve from lightfuel to heavyfuel' responsive to' apre- Vselected speednand load on said en`g'ine,`and tirn'edelay mean-s for operating `the eturn fuel selector; valve toofsaid heavy f uelback to itsV sourcev of supply.

s. A fuer systemV for supplying two dis fianet fe'is 'to fuel',4comprising means for constantly cir heatingv al source of heavy fuel'vtolowei-Y its under pressure; a three-Way?v inletv fuelY selec of 'valveinlet ports' and a eonnectioriV between'the so of said inlet fuelselector valve leadingt a Vsingle inlet port leading frmtlie e twoseparate out-let ports, the outletf'poit of said inletifuel';

selector valve being in connectionwith one'of the outlet ports of saidr'eturnfuel selector valve; `Itilieothefof saidn VVoutlet ports of saidreturn fuel'seleictoivlvebing in conuectionewiththe sourcer` of supplyof'h s'vyffu'eh `and time delay means'for maintaining Ythei ret'ufiielselector' 9`.Y A fuel supply systemsupplying'ltuo'-dissinilarfuel,` comprising incansfory supplying'thelight fuel to' saidV engine'for idling-'and light loadfconditio'ns,means/fof.

heavy fuel tank, a. second heat exchanger within'said second tank, VandV in pressure connection with vthe heavy fuel tank, Vand ilt'erunitsvvithin the seondtank and with the second heat eitchangei', withareturn' circuit to the heavy fuel tnk-and -to said Diesel engine.

1 1. A 'fuel system foi` Diesel engines-as disclosed, `in cluding aheavy fuel ltank having an inlet and anoutlet and adapted to h oldheavyfuel, a second tank in connection V"vi/ith the Diesel engine .forconducting engineheat thereto, a heat exchanger said second tanky and inpressure connection with the inlet and outlet of saidheavy fuel tank, asecond 'heat 'exchanger withinsaid second tank, and in pressureconnection with the heavy fuel tank, lilter units Within the second tankyand with Vthe second heat exchanger, vvitl a returncircuit to the heavyfuel tank and to` sai'd Diesel engine, and means f orgiirect-v ing heavyfuel from the filter units toan inlet fuel selector valve totheDieselengine and a eturn f uel selector valve for directing said heavy fuelYto the heavy f eltank.

l2. A fuel `system vfor supplying two dissimilar fuels to the manifoldofa Dieselengine, inea'ns for supplying oneV of said tv'vo Vfuels"ytosail manifold, means for automatically changing fi'orh therst tothesecond of said two fuels and vice versa, ata .pi-determined speed orload of said Diesel engine, and means rfenderingsaid automatic meansineffective whereby, one or the other of said two fuels may beselectively and instantaneously supplied to the manifold of saidV.engine t all engine speedsV and e loads.

Y through of eithe'rof said fuels, a return fuel selector 13. A systemfor supplyingtvvodissimilarhels to a Y Diesel engine, vcoinpiisiifgJelect'rical v time delay means operative `in accordance withpredetermined engine speed valve for said fuels, one of; Vfuels beingdeadended at said return fuel selector valve when theother of said fuelsis passing therethrough, elodie-pneumaticsolenoid valves in circuit withsaid electfical'relay for controlling pressureilid tosid inlet andreturnfuel s fefleetor valves Y Y Vmeans for constantly supplying light'fuelfr n a'souce to lmove the sante', faitirne delay unit controlling oper-vation of Vthe electrfopneuinatic solenoid valve supplying pressn'refluidto the' return' fueisejleeltor v1ve. 14. The devi'ceas set forth-'inclaim 1 3, characterized f in het @energizing'theje1eetnea1 veirenit tothe eieetrie relay consequent upon engine load and speed, Vopening Vsaidrelay,'-and releasing pressure fluid from the fuel selector valve tornove the saine toa position for pass age of one of said fuels, thecicuit Ato ythe time delay unit being V1'na`inta-ined forV a tir'r'ielinterval, followed bythe second electropneumatic sol oid Valvejbeingdeenergiz'ed and for shifting the position of the return fuelselectoi-,valve toreceive the fuel passing through said inlet fuelselector valve. Y

151.V VA dual"ful systen1 for Diesel engines', the engine having amanifold provided v/ithan inletand an outlet movable valve nemlje'ij,means of o onnec tion betweena tiret of een eaves withV the' inlet ofsaidV manifold, ein means of connection betvveen'; tle` outl etofsaid'nianifold fuel, separate means of connection with the'rs't ofrsaidvai-ee with Aeeen seme; efjfueifgspply, whereby when supplying Itosaid'engine the'heavy fuel at' predetermined;

load change on; said engine; andi means preventing theconsumption ofmixed fuels by 'th'engiueduring'clilang'el over from'heavyfuelttoli'ghtfuels l0. Alfu'el system for' Diesel enginesasdisclosed inecluding' ai heavy fuel lrlavin'g'V inletaiid: an outlet ema-, adaptedte herey heavy' nel; e sees-nf een'.

the movable valve men1be"r. in theY first andthe second of said valvesis inoneposition, o neof said fuels is di-` rected `through the' firstofsaid valves to the manifold inlet, the second of saidvalves'directing'thefuel from the outlet of said manifold back to thesource of supply ofr said fuel.

16. A` dual fuelisystem for Diesel engines, the engine having a manifoldprovided with an inlet and an outlet for fuel, comprising: a pair ofvalves, each including a movable member, means of connection between arst of said valves with the inlet of said manifold, and means ofconnection between the outlet of said manifold with the second of saidvalves, and means of connection between the second valve and a source ofsupply for one fuel, separate means of connection with the first of saidvalves with each source of fuel supply, whereby When the movable valvemember in the first and the second of sa-id valves is in one position,one of said fuels is directed through the rst of said valves to themanifold inlet, the second of said valves directing the fuel from theoutlet of said manifold back to the source of supply of said fuel, andthe rst and second of said valves, when the movable valve members are ina second position, both directing the other of said fuels to the inletof the manifold.

17. A dual fuel system for Diesel engines, the engine having a manifoldprovided with an inlet and an outlet for fuel, comprising: A pair ofvalves, each including a movable member, means of connect-ion between afirst of said valves with the inlet of said manifold, and means ofconnection -between vthe outlet of said manifold with the second of saidvalves, and means of connection between the second valve and a source ofsupply for one fuel, separate means of connection with the rst of saidvalves wit-h each source of fuel supply, whereby when the movable valvemember in the rst and the second of said valves is in one position, oneof said fuels is directed through the first of said valves to themanifold inlet, the second of said valves directing the fuel from theoutlet of said manifold back to the source of supply of said fuel, therst and second of said valves, when the movable valve members are in asecond position, both directing the other of said fuels to the -inlet ofthe manifold, and automatic means for controlling the position of eachmovable valve member in accordance with engine speed and load.

18. A dual fuel system for supplying two dissimilar fuels such as aheavy and a light fuel to a Diesel engine manifold, comprising:automatic means for switching from heavy -fuel to light lfuel and viceversa, at a preselected load and speed of said Diesel engine, and meansfor automatically purging the heavy fuel supplied to the engine manifoldprior to supplying light fuel to prevent contamination in the enginemanifold between the fuels.

References Cited in the le of this patent UNITED STATES PATENTS

